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[20160805]logminer使用问题3.txt

原创 Oracle 作者：lfree 时间：2016-08-05 11:05:25 0 删除 编辑

[20160805]logminer使用问题3.txt

--前一阵子看itpub有人想通过logminer来抽取归档同步数据库，实际上这个非常不科学，存在一定的风险，我觉得很多情况下会漏掉一些sql
--语句，通过例子来说明。

--首先说明logminer用来补救一些异常操作还是可行的。

1.测试环境说明：
SCOTT@book> @ &r/ver1

PORT_STRING                    VERSION        BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx            11.2.0.4.0     Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

SCOTT@book> alter database add supplemental log data;
Database altered.

SCOTT@book> alter database  FORCE LOGGING ;
Database altered.

SCOTT@book> select SUPPLEMENTAL_LOG_DATA_MIN, FORCE_LOGGING  from v$database ;
SUPPLEME FOR
-------- ---
YES      YES

--上次我说明如果提交在另外一个归档里，你的分析可能会都掉一些dml操作语句。这次测试行迁移。

create table t (id number,name varchar2(2000));
insert into t (id)  select rownum from dual connect by level<=10;
commit ;

2.测试1：
SCOTT@book> alter system archive log current ;
System altered.

SCOTT@book> @ &r/logfile
GROUP# THREAD# SEQUENCE#       BYTES BLOCKSIZE MEMBERS ARC STATUS     FIRST_CHANGE# FIRST_TIME          NEXT_CHANGE# NEXT_TIME           GROUP# STATUS     TYPE       MEMBER                       IS_
------ ------- --------- ----------- --------- ------- --- ---------- ------------- ------------------- ------------ ------------------- ------ ---------- ---------- ---------------------------- ---
     1       1       412    52428800       512       1 YES INACTIVE     13245387388 2016-08-05 09:41:47  13245387725 2016-08-05 09:56:07      1            ONLINE     /mnt/ramdisk/book/redo01.log NO
     2       1       413    52428800       512       1 YES ACTIVE       13245387725 2016-08-05 09:56:07  13245388532 2016-08-05 10:09:36      2            ONLINE     /mnt/ramdisk/book/redo02.log NO
     3       1       414    52428800       512       1 NO  CURRENT      13245388532 2016-08-05 10:09:36 2.814750E+14                          3            ONLINE     /mnt/ramdisk/book/redo03.log NO

--当前使用/mnt/ramdisk/book/redo02.log。
SCOTT@book> update t set name=lpad('x',2000,'x');
10 rows updated.

SCOTT@book> commit ;
Commit complete.

SCOTT@book> analyze table t list chained rows;
Table analyzed.

SCOTT@book> analyze table t compute statistics;
Table analyzed.

SCOTT@book> select table_name, num_rows, chain_cnt, avg_row_len from user_tables where table_name='T';
TABLE_NAME   NUM_ROWS  CHAIN_CNT AVG_ROW_LEN
---------- ---------- ---------- -----------
T                  10          7        2013
--发生了行迁移。
SCOTT@book> @ &r/rowid AAAXY5AAEAAAALuAAA
    OBJECT       FILE      BLOCK        ROW DBA                  TEXT
---------- ---------- ---------- ---------- -------------------- ----------------------------------------
     95801          4        750          0 4,750                alter system dump datafile 4 block 750 ;

SCOTT@book> alter system archive log current ;
System altered.

--分析这个归档日志。
$ ls -l /u01/app/oracle/archivelog/book/1_414_907434361.dbf
-rw-r----- 1 oracle oinstall 38912 2016-08-05 10:11:49 /u01/app/oracle/archivelog/book/1_414_907434361.dbf

$ strings /u01/app/oracle/archivelog/book/1_414_907434361.dbf | grep xxxxx | head -1
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

--//使用logminer分析：
Begin
  SYS.DBMS_LOGMNR.ADD_LOGFILE( '/u01/app/oracle/archivelog/book/1_414_907434361.dbf', sys.dbms_logmnr.New);
end;

Begin
  SYS.DBMS_LOGMNR.START_LOGMNR ( Options => sys.dbms_logmnr.DICT_FROM_ONLINE_CATALOG+sys.dbms_logmnr.COMMITTED_DATA_ONLY);
end;

SCOTT@book> select row_id,substr(sql_redo,1,90) c90,substr(sql_undo,1,90) c90  from v$logmnr_contents  where seg_name='T' order by 1;
ROW_ID             C90                                                                                        C90
------------------ ------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------
AAAXY5AAEAAAALuAAA update "SCOTT"."T" set "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "NAME" = NULL where "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
AAAXY5AAEAAAALuAAB update "SCOTT"."T" set "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "NAME" = NULL where "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
AAAXY5AAEAAAALuAAC update "SCOTT"."T" set "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "NAME" = NULL where "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
AAAXY5AAEAAAALuAAD update "SCOTT"."T" set "ID" = '4', "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "ID" = '4', "NAME" = NULL where "ID" = '4' and "NAME" = 'xxxxxxxxxx
AAAXY5AAEAAAALuAAE update "SCOTT"."T" set "ID" = '5', "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "ID" = '5', "NAME" = NULL where "ID" = '5' and "NAME" = 'xxxxxxxxxx
AAAXY5AAEAAAALuAAF update "SCOTT"."T" set "ID" = '6', "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "ID" = '6', "NAME" = NULL where "ID" = '6' and "NAME" = 'xxxxxxxxxx
AAAXY5AAEAAAALuAAG update "SCOTT"."T" set "ID" = '7', "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "ID" = '7', "NAME" = NULL where "ID" = '7' and "NAME" = 'xxxxxxxxxx
AAAXY5AAEAAAALuAAH update "SCOTT"."T" set "ID" = '8', "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "ID" = '8', "NAME" = NULL where "ID" = '8' and "NAME" = 'xxxxxxxxxx
AAAXY5AAEAAAALuAAI update "SCOTT"."T" set "ID" = '9', "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "ID" = '9', "NAME" = NULL where "ID" = '9' and "NAME" = 'xxxxxxxxxx
AAAXY5AAEAAAALuAAJ update "SCOTT"."T" set "ID" = '10', "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "ID" = '10', "NAME" = NULL where "ID" = '10' and "NAME" = 'xxxxxxxx
10 rows selected.

--注意看rowid=AAAXY5AAEAAAALuAAA的那行，与最后的几条不同.

SCOTT@book> select sql_redo c100 ,sql_undo c100  from v$logmnr_contents  where seg_name='T' and row_id='AAAXY5AAEAAAALuAAA';
C100                                                                                                 C100
---------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------
update "SCOTT"."T" set "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "NAME" = NULL where "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
.....
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' where "NAME" IS NULL and ROWID = 'AAAXY5AAEAAAALuAAA';            xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' and ROWID = 'AAAXY5AAEAAAALuAAA';


SCOTT@book> select sql_redo c100 ,sql_undo c100  from v$logmnr_contents  where seg_name='T' and row_id='AAAXY5AAEAAAALuAAD';
C100                                                                                                 C100
---------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------
update "SCOTT"."T" set "ID" = '4', "NAME" = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx update "SCOTT"."T" set "ID" = '4', "NAME" = NULL where "ID" = '4' and "NAME" = 'xxxxxxxxxxxxxxxxxxxx
...
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' where "ID" = '4' and "NAME" IS NULL and ROWID = 'AAAX xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' and ROWID = 'AAAXY
Y5AAEAAAALuAAD';                                                                                     5AAEAAAALuAAD';

--//注中间x被截断了。
BBED> x /rx *kdbr[0]
rowdata[4081]                               @6119
-------------
flag@6119: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@6120: 0x02
cols@6121:    2

col    0[2] @6122:  0xc1  0x02
col 1[2000] @6125:  0x78  0x78  0x78  0x78 ....

BBED> x /rx *kdbr[3]
rowdata[54]                                 @2092
-----------
flag@2092: 0x20 (KDRHFH)
lock@2093: 0x02
cols@2094:    0
nrid@2095:0x010002ef.0

--注意看发生行迁移的行与没有发生行迁移的行记录的格式不一样。
--另外我没有主键，也就是如果你去掉条件 ROWID = 'AAAXY5AAEAAAALuAAA';   前面的操作会很危险。

3.重复测试建立所以看看。

create table tx (id number,name varchar2(2000));
insert into tx (id)  select rownum from dual connect by level<=10;
create unique index pk_tx on tx(id);
alter table tx add constraint pk_tx primary key (id) enable validate;
commit ;

alter system archive log current ;

SCOTT@book> @ &r/logfile
GROUP# THREAD# SEQUENCE#       BYTES BLOCKSIZE MEMBERS ARC STATUS     FIRST_CHANGE# FIRST_TIME          NEXT_CHANGE# NEXT_TIME           GROUP# STATUS     TYPE       MEMBER                       IS_
------ ------- --------- ----------- --------- ------- --- ---------- ------------- ------------------- ------------ ------------------- ------ ---------- ---------- ---------------------------- ---
     1       1       415    52428800       512       1 YES ACTIVE       13245388596 2016-08-05 10:11:49  13245389809 2016-08-05 10:36:39      1            ONLINE     /mnt/ramdisk/book/redo01.log NO
     2       1       416    52428800       512       1 NO  CURRENT      13245389809 2016-08-05 10:36:39 2.814750E+14                          2            ONLINE     /mnt/ramdisk/book/redo02.log NO
     3       1       414    52428800       512       1 YES INACTIVE     13245388532 2016-08-05 10:09:36  13245388596 2016-08-05 10:11:49      3            ONLINE     /mnt/ramdisk/book/redo03.log NO

--当前redo seq=416.

SCOTT@book> update tx set name=lpad('y',2000,'y');
10 rows updated.

SCOTT@book> commit ;
Commit complete.

SCOTT@book> analyze table tx list chained rows;
Table analyzed.

SCOTT@book> analyze table t compute statistics;
Table analyzed.

SCOTT@book> select table_name, num_rows, chain_cnt, avg_row_len from user_tables where table_name='TX';
TABLE_NAME   NUM_ROWS  CHAIN_CNT AVG_ROW_LEN
---------- ---------- ---------- -----------
TX                 10          7        2013

--分析这个归档日志。
Begin
  SYS.DBMS_LOGMNR.ADD_LOGFILE( '/u01/app/oracle/archivelog/book/1_416_907434361.dbf', sys.dbms_logmnr.New);
end;

Begin
  SYS.DBMS_LOGMNR.START_LOGMNR ( Options => sys.dbms_logmnr.DICT_FROM_ONLINE_CATALOG+sys.dbms_logmnr.COMMITTED_DATA_ONLY);
end;

SCOTT@book> select row_id,substr(sql_redo,1,90) c90,substr(sql_undo,1,90) c90  from v$logmnr_contents  where seg_name='TX' order by 1;
ROW_ID             C90                                                                                        C90
------------------ ------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------
AAAAAAAAAAAAAAAAAB analyze table tx compute statistics;
AAAAAAAAAAAAAAAAAB analyze table tx list chained rows;
AAAXY7AAEAAAAL0AAA update "SCOTT"."TX" set "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "NAME" = NULL where "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
AAAXY7AAEAAAAL0AAB update "SCOTT"."TX" set "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "NAME" = NULL where "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
AAAXY7AAEAAAAL0AAC update "SCOTT"."TX" set "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "NAME" = NULL where "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
AAAXY7AAEAAAAL0AAD update "SCOTT"."TX" set "ID" = '4', "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "ID" = '4', "NAME" = NULL where "ID" = '4' and "NAME" = 'yyyyyyyyy
AAAXY7AAEAAAAL0AAE update "SCOTT"."TX" set "ID" = '5', "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "ID" = '5', "NAME" = NULL where "ID" = '5' and "NAME" = 'yyyyyyyyy
AAAXY7AAEAAAAL0AAF update "SCOTT"."TX" set "ID" = '6', "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "ID" = '6', "NAME" = NULL where "ID" = '6' and "NAME" = 'yyyyyyyyy
AAAXY7AAEAAAAL0AAG update "SCOTT"."TX" set "ID" = '7', "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "ID" = '7', "NAME" = NULL where "ID" = '7' and "NAME" = 'yyyyyyyyy
AAAXY7AAEAAAAL0AAH update "SCOTT"."TX" set "ID" = '8', "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "ID" = '8', "NAME" = NULL where "ID" = '8' and "NAME" = 'yyyyyyyyy
AAAXY7AAEAAAAL0AAI update "SCOTT"."TX" set "ID" = '9', "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "ID" = '9', "NAME" = NULL where "ID" = '9' and "NAME" = 'yyyyyyyyy
AAAXY7AAEAAAAL0AAJ update "SCOTT"."TX" set "ID" = '10', "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "ID" = '10', "NAME" = NULL where "ID" = '10' and "NAME" = 'yyyyyyy
12 rows selected.


SCOTT@book> select sql_redo c100 ,sql_undo c100  from v$logmnr_contents  where seg_name='TX' and row_id='AAAXY7AAEAAAAL0AAA';
C100                                                                                                 C100
---------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------
update "SCOTT"."TX" set "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy update "SCOTT"."TX" set "NAME" = NULL where "NAME" = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
...
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy' where "NAME" IS NULL and ROWID = 'AAAXY7AAEAAAAL0AAA';           yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy' and ROWID = 'AAAXY7AAEAAAAL0AAA';

--这样要在where条件里加入主键，必须要修改附加日志的级别内容。
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS;
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (UNIQUE) COLUMNS;
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (FOREIGN KEY) COLUMNS;
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;

SELECT supplemental_log_data_min, supplemental_log_data_pk, supplemental_log_data_ui, supplemental_log_data_fk, supplemental_log_data_all FROM v$database;

--这样务必带来日志的增加。要仔细评估这些风险。

--总之：你要实现它同步要打开更多的附加日志才行。

来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/267265/viewspace-2123025/ ，如需转载，请注明出处，否则将追究法律责任。

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lfree
专家姓名：张文胜
熟悉oracle相关技术，擅长sql优化，rman备份与恢复，熟悉linux shell编程。

注册时间：2008-01-03

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